adp 1 : multi-role combat aircraft

DESIGN OF A MULTIROLE COMBAT AIRCRAFT

AIRCRAFT DESIGN PROJECT- 1 REPORT

Submitted by

SARANYA.N

TASNEEM.RASHID

in partial fulfillment for the award of the degree

of

BACHELOR OF ENGINEERING

in

AERONAUTICAL ENGINEERING

RAJALAKSHMI ENGINEERING COLLEGE

ANNA UNIVERSITY:: CHENNAI 600 025

APRIL 20I2

1

ACKNOWLEDGEMENT

I would like to extent my heartfelt thanks to Prof. Yokesh Kumar Sinha (Head of aeronautical department) for giving me his able support and encouragement. At this juncture I must emphasis the point that this design project would not have been possible without the highly informative and valuable guidance by Prof .P.S. Venkatnarayanan, whose vast knowledge and experience has must us go about this project with great care. we have great pleasure in expressing our sincere and whole hearted gratitude to them. It is worth mentioning about my team mates , friends and colleagues of the aeronautical department, for extending their kind help whenever the necessity arose. I thank one and all who have directly or indirectly helped me in making this design.

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INDEX

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Serial no.

Content Page no

1. Aim 2. Abstract 3. Introduction 4. Design sequence 5. Collection of similar

aircraft and data retrieval6. Comparative data sheet7. Design graphs8. Design data sheet9. Mission specification10. Weight estimation11. Power plant selection12. Airfoil selection13. Performance calculation 14. Three view diagram15. Conclusion16. Bibliographies and

references

ABSTRACT

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ABSTRACT:

Our project is the design of a multirole combat aircraft. A multirole combat

aircraft is an aircraft designed to perform different roles in combat. The air-to-

air combat role has been normally performed by fighter aircraft. In addition a

multirole fighter has secondary roles such as air-to-surface attack .

The term multirole has been reserved for aircraft designed with the aim of using

a common airframe for multiple tasks where the same basic airframe is adapted

to a number of differing roles. The main motivation for developing multirole

aircraft is cost reduction in using a common airframe.

The project report comprises of a literature survey of about 22 fighter aircrafts

Based on it a number of graphs were drawn to get a rough idea of the

specifications of the aircraft.. After this an appropriate airfoil is selected and its

important parameters are calculated. Then the wing loading estimation is done

using two constraints and further the thrust to weight ratio is estimated using

three constraints. Using this thrust is calculated in order to select an appropriate

engine. Finally performance graphs are drawn and a 3-view diagram of the

aircraft is drawn

Our multirole fighter is a single seater powered by twin turbofan engines ,

flying at Mach 2 with a range of 2000km.

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http://en.wikipedia.org/wiki/Ground-attack_aircraft

http://en.wikipedia.org/wiki/Fighter_aircraft

http://en.wikipedia.org/wiki/Aircraft

LIST OF TABLES

S.NO DESCRIPTION

1 Suggested fuel fractions for several mission phases

2 Suggested values for L/D, cj, ηp & cp for several mission phases

3 Equivalent skin friction coefficients

4 Values for CDO, e, for various types of aircrafts

5 Thrust to weight ratio for various types of aircrafts

LIST OF FIGURES

1. Graphs of various parameters Vs cruise speed

2. Weight trends for fighters

3. Mission Profile

4. 3-view diagram of multirole combat aircraft

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LIST OF SYMBOLS, ABBREVIATIONS AND NOMENCLATURE

1. CD-Drag coefficient2. CDO-Zero lift drag coefficient3. Cj-Specific fuel consumption for jet engine4. CL-Lift coefficient5. Cp –Specific fuel consumption for propeller driven aircraft6. e-Ostwald efficiency factor7. g-Acceleration due to gravity8. L/D-Lift to drag ratio9. Mff-Mission fuel fraction10.N-time increment for free roll just after touchdown, before brakes are

applied11.R/C-Rate of climb12.R-Range of the aircraft13.sa –Approach distance14.sf –Flare distance15.sg –ground roll16.S-Wing area17.V∞-Free stream velocity18.Vf-Flare velocity19.Vstall-Stall velocity20.W/S-Wing loading21.Wcrew-Crew Weight22.WE-Empty weight23.WF(res)-Reserve fuel weight24.WF(used)-Weight of the fuel used during the mission25.WPL-Payload weight26.WTFO-Trapped fuel weight27.WTO-Takeoff weight28.ηp -Propeller efficiency29.ρ∞ -Free stream density at sea level

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INTRODUCTION

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INTRODUCTION:

A multirole combat aircraft is an aircraft designed to perform different roles in combat. The air-to-air combat role has been normally performed by fighter aircraft. So a multirole combat aircraft with air combat role and other secondary role such as air-to-surface attack is as often called a multirole fighter. The term has been reserved for aircraft designed with the aim of using a common airframe for multiple tasks where the same basic airframe is adapted to a number of differing roles. Originally the term was used for a common airframe built in a number of different variants for different roles. Multirole has also been applied to one aircraft with both major roles, for example:

a primary air-to-air combat role

a secondary role like air-to-surface attack.

More roles can be added, such as air reconnaissance, forward air control, and electronic warfare. Attack missions include the subtypes air interdiction, suppression of enemy air defence (SEAD), and close air support (CAS).

The main motivation for developing multirole aircraft is cost reduction in using a common airframe.

DESIGN OF AN AIRPLANE:

Airplane design is both an art and a science. Its the intellectual engineering process of creating on paper(or on a computer screen) a flying machine to

meet certain specifications and requirements established by potential users( or as perceived by the manufacturer) and

pioneer innovative, new ideas and technology

The design process is indeed an intellectual activity that is rather specified one that is tempered by good intuition developed via by attention paid to successful airplane designs that have been used in the past, and by (generally proprietary) design procedure and databases(hand books etc) that are a part of every airplane manufacturer

PHASES OF AIRPLANE DESIGN:

The complete design process has gone through three distinct phases that are carried out in sequence. They are

Conceptual design

10

http://en.wikipedia.org/wiki/Close_air_support

http://en.wikipedia.org/wiki/Close_air_support

http://en.wikipedia.org/wiki/Suppression_of_enemy_air_defense

http://en.wikipedia.org/wiki/Air_interdiction

http://en.wikipedia.org/wiki/Air_interdiction

http://en.wikipedia.org/wiki/Electronic_warfare

http://en.wikipedia.org/wiki/Forward_air_control

http://en.wikipedia.org/wiki/Air_reconnaissance



http://en.wikipedia.org/wiki/Fighter_aircraft

http://en.wikipedia.org/wiki/Aircraft

Preliminary design Detailed design

CONCEPTUAL DESIGN:

The design process starts with a set of specifications (requirements)for a new airplane, or much less frequently as the response to the desire to implement some pioneering, innovative new ideas and technology. In either case, there is a rather concrete good towards which the designers are aiming. The first steps towards achieving that goal constitute the conceptual design phase. Here, within a certain somewhat fuzzy latitude, the overall shape , size, weight and performance of the new design are determined.

The product of the conceptual design phase is a layout on a paper or on a computer screen) of the airplane configuration. But one has to visualize this drawing as one with flexible lines, capable of being slightly changed during the preliminary design phase. However the conceptual design phase determines such fundamental aspects as the shape of the wings(swept back, swept forward or straight), the location of the wings related to the fuselage, the shape and location of the horizontal and vertical tail, the use of a engine size and placement etc, the major drivers during the conceptual design process are aerodynamics, propulsion and flight performance.

Structural and context system considerations are not dealt with in any detail. However they are not totally absent. During the conceptual design phase the designer is influenced by such qualitative as the increased structural loads imposed by a high horizontal tail location trough the fuselage, and the difficulties associated with cutouts in the wing structure if the landing gear are to be retracted into the wing rather than the fuselage or engine nacelle. No part of the design is ever carried out in a total vacuum unrelated to the other parts.

PRELIMINARY DESIGN:

In the preliminary design phase, only minor changes are made to the configuration layout (indeed, if major changes were demanded during this phase, the conceptual design process have been actually flawed to begin with. It is in the preliminary design phase that serious structural and control system analysis and design take place.

During the phase also, substantial wind tunnel testing will be carried out and major computational fluid dynamics (CFD)

Calculations of the computer flow fluid over the airplane configurations

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Its possible that the wind tunnel tests the CFD calculations will in cover some undesirable aerodynamic interference or some unexpected stability problems which will promote change to the configuration layout

At the end of preliminary design phase the airplane configuration is frozen and preciously defined. The drawing process called lofting is carried out which mathematically models the precise shape of the outside skin of the airplane making certain that all sections of the aircraft property fit together

The end of the preliminary design phase brings a major concept to commit the manufacture of the airplane or not. The importance of this decision point for modern aircraft manufacturers cannot be understated, considering the tremendous costs involved in the design and manufacture of a new airplane. This is no better illustrated.

DETAIL DESIGN:

The detail design phase is literally the nuts and bolts phase of airplane design. The aerodynamic, propulsion, structures performance and flight control analysis have all been finished with the preliminary design phase. For detail design. The airplane is now simply a machine to be fabricated. The pressure design of each. Individual rib, spar and section of skin now take place. The size of number and location of fastness are determined. At this stage, flight simulators for the airplane are developed. And these are just a few of the many detailed requirements during the detail design phase. At the end of this phase, the aircraft is ready to be fabricated.

THE SEVEN INTELLECTUAL PIVOT POINTS FOR CONCEPTUAL DESIGN:

The design process is an art of creativity and like all creative creatures, there is no one correct and absolute method to carry it out. However conceptual design can be imagined at an array of the seven points at strategic locations in some kind of intellectual space, and these pivot points are connected by a verb of detailed approaches. The web constructed by different people would be different, although the pivot points should be the same ,due tp their fundamental significance.

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BLOCK ARRAY FOR CONCEPTUAL DESIGN

1.REQUIREMENTS

2.WEIGHT OF THE AIRPLANE-FIRST ESTIMAE

3.CRITICAL PERFORMANCE PARAMETERS

MAX LIFT CO-EFFICIENT(CL)max

LIFT TO DRAG RATIO, L/D

WING LOADING, W/S

THRUST TO WEIGHT RATIO, T/W

4. CONFIGURATION LAYOUT-SHAPE AND SIE OF THE AIRPLANE ON A DRAWING (OR COPMUTER SCREEN)

5. BETTERWEIGHT ESTIMATE

6. PERFORMANCE ANALYSIS- DOES THE DESIGN MEET EXCEED REQUIREMENTS?

YES

7. OPTIMIZATION –IS IT THE BEST DESIGN?

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REQUIREMENTS:

Requirements for a new airplane design are as unique and different

from one airplane to another as fingerprints are from one. However being to

another. Hence we cannot stipulate in this section a specific, standard form to

use to write requirements there is none.

For any new airplane design. There must be some established

requirements which serve as the jumping off point for the design process, and

which serve as the focused goal for the completed design. Typical aspects are

frequently stipulated in the requirements are some combination of the following

RANGE

TAKE OFF DISTANCE

STALLING VELOCITY

ENDURANCE

MAXIMUM VELOCITY

RATE OF CLIMB

MAXIMUM LOAD FACTOR

SERVICE CEILING

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DESIGN SEQUENCE

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DESIGN SEQUENCE

1. Collection of existing similar aircraft data

2. Retrivel of data

3. Design graphs

4. Preparation of design data sheet

5. Mission specification

6. Weight estimation

Mission fuel weight estimation

Operating tentative weight estimation

Operating empty weight estimation

Empty weight estimation

Payload weight estimation

Overall takeoff weight estimation

7. Airfoil selection

8. Wing loading estimation

Based on stall velocity

Based on Landing distance

Calculation of wing area

9. Thrust to weight ratio estimation

Based on takeoff distance

Based on max rate of climb

Based on max velocity

Calculation of thrust

10.Power plant selection

11.Performance curves

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LITERATURE SURVEY

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LITERATURE SURVEY

It’s the collection of data of various airplanes to consolidate the data for the

airplane that we design. Around 22 airplanes with their design parameters are

compared.

AIRCRAFT FOR REFERENCE:

Falcon F16

Sukhoi -30

MIG 29

Thunderbolt A10

Eurofighter typhoon

Chengdu J10

Harrier

Raptor F22

Mirrage 2000D

Rafale

Super hornet F18

Gripen

Tejas

Eagle F15

Mitsubishi F2

CAC F7

Finback F8

FBC

Jaguar

AMX

Lightning F35

Sukhoi 25

FALCON 16

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S.NO PARAMETER VALUE

1. Max Take off weight(kg) 19,200

2. Wing loading(kg/m2) 431

3. Wing span(m) 9.96

4. Thrust(kN) 127

5. Thrust to weight ratio 1.095

6. Cruise speed(mach no) 2

7. Rate of climb(m/min) 15240

8. Service ceiling(m) 18000

9. Range(km) 3222.5

10. Crew 1

11. Climb speed(km/hr) 2414

SUKHOI 30

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1. Max Take off weight(kg) 44350



4. Thrust(kN) 83.4

5. Thrust to weight ratio 1

6. Cruise speed(mach no) 1.9



9. Range(km) 3000

10. Crew 2

11. Climb speed(km/hr) 2280.4

MIG 29

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4. Thrust(kN) 86.4





9. Range(km) 1430

10. Crew 1


THUNDERBOLT A10

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1. Max Take off weight(kg) 23133.2



4. Thrust(kN) 40.34



7. Rate of climb(m/min) 1828.8


9. Range(km) 1287.48

10. Crew 1


TYPHOON

22





4. Thrust(kN) 90





9. Range(km) 2900

10. Crew 1


F22 RAPTOR

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2. Wing loading(kg/m2) 348.7


4. Thrust(kN) 155.7



7. Rate of climb(m/min)


9. Range(km) 2960

10. Crew 1


MIRRAGE

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4. Thrust(kN) 64.3





9. Range(km) 1550

10. Crew 1

11. Climb speed(km/hr)

HORNET

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1. Max Take off weight(kg) 25401.2



4. Thrust(kN) 80.1





9. Range(km) 2000

10. Crew 1

11. Climb speed(km/hr)

DASSAULT RAFALE

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4. Thrust(kN) 133.5





9. Range(km) 3700

10. Crew 1


GRPPEN

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3. Wing span(m) 8.4

4. Thrust(kN) 80



7. Rate of climb(m/min)


9. Range(km) 1430

10. Crew 2


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COMPARATIVE DATA SHEET

COMPARATIVE DATA SHEET

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AIRCRAFT

NAME

Max T/O

WEIGHT

(kg)

WING

LOADING

(kg/m2)

WING

SPAN

(m)

THRUST

(kN)

T/W

RATIO

CRUISE

SPEED

(mach

no)

RATE

OF

CLIMB

(m/min)

SERVIC

E

CEILING

(m)

RANGE

(km)

CREW CLIMB

SPEED

(km/hr)

FALCON F16 19200 431 9.96 127 1.095 2 15240 18000 3222.5 1 2414

SUKHOI 30 44350 401 14.69 83.4 1 1.9 13800 17500 3000 2 2280.4

MIG 29 15300 442 11 98.79 1.09 2.25 15120 18013 1676 1 2430.1

THUNDERBOLT

A10

25133.2 482 17.56 40.34 0.36 1.65 1828.8 13700 1287.48 1 675.9

EUROFIGHTER

TYPHOON

23500 312 10.96 90 1.15 2 18897.6 19810 2900 1 2386.7

RAPTOR F22 27216 348.7 13.56 155.7 1.09 2.25 15240 2960 1 2449.42

MIRAGE 2000D 17500 414.6 9.13 64.3 0.91 2.2 17068.8 17060 1550 1

RAFALE 24500 536.1 10.8 133.5 1.1 1.8 18290 16800 3700 2 1390.47

HORNET F18 25401.2 454 12.3 80.1 0.96 1.8 13716 15240 2000 2

GRIPEN 14000 283 8.4 80 0.97 2 15240 1430 2 1408.2

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DESIGN GRAPHS

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CLIMB SPEED VS CRUISE SPEED

RANGE VS CRUISE SPEED

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RATE OF CLIMB VS CRUISE SPEED

SERVICE CEILING VS CRUISE SPEED

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TAKE OFF WEIGHT VS CRUISE SPEED

THRUST TO WEIGHT RATIO VS CRUISE SPEED

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THRUST VS CRUISE SPEED

WING LOADING VS CRUISE SPEED

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WING SPAN VS CRUISE SPEED

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MISSION PROFILE

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CONSOLIDATED DATA

1. NAME : BATTLE

2. RANGE : 2000km

3. CREW : 1

4. MACH NO : 2

5. SERVICE CELING : 17000 m

6. CLIMB SPEED : 1875 km/hr

7. RATE OF CLIMB : 25.42 m/s

8. T/W RATIO : 1

9. THRUST : 90 KN with aft/burn

10.WING SPAN : 11.25 m

11.WING LOADING : 335 kg/m2

12.TAKE OFF WEIGHT : 2000 kg

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WEIGHT ESTIMATION

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AIM: To estimate the following parameters of our conceptual design

1. Gross/take-off weight(WTO)2. Em pty weight (WE)3. Mission fuel weight(WE)

PROCESS IN WEIGHT ESTIMATION Process begins with guess take-off weight from consolidate data The payload weight is determined from the requirements Fuel required for the mission is calculated as fraction of the guess

take-off weight WF = WF(used) + WF(res)

WF(used) =(1-Mff)(WTO)guess

WF(res) =25%of WF(used)

Tentative value of empty weight is calculated using WE(tent) =(WTO)guess - WPL-Wcrew-WF-WTFO

WTFO =0.5% of (WTO)guess

The tentative empty weight is compared with allowable empty weight, which is given by the formula referred from Roshkam

(WE)allowable=Antilog10[log10(WTO)guess-A/B] Improved guesses are then made and iterations processed until

convergence.

CATEGORIES OF WEIGHT OF AN AIRPLANECREW WEIGHT (WCREW) The crew comprises the people necessary to operate the airplane in flight. For our airplane the crew is simply the trainer and the trainee.

PAYLOAD WEIGHT (WPL) The payload is what the airplane is intended to transport passenger, baggage, freight etc. if the airplane is intended for military combat use. The payload includes bombs, rockets and other disposable ordnance.

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FUEL WEIGHT(WF) This is the weight of the fuel in the fuel tanks. Since fuel is consumed during the course of the flight, WF is variable, decreasing with time during the flight.

EMPTY WEIGHT(WE) This is the weight of everything else the structure, engines(with all accessory equipment), electronic equipment (including radar, computers, communication devices etc), landing gear, fixed equipment (seats, galleys, etc) and anything else that is not crew, payload or fuel WE =WME+WFEQ

WME =Manufacturer’s empty weight WFEQ=Fixed equipment weight

TAKE OFF GROSS WEIGHT(WTO) It is the weight of the airplane at the instant it begins its mission. It includes the weight of all the fuel on board at the beginning of the flight, hence WTO= WCrew + WPL + WF + WE

Where WF is the weight of the full load at the beginning of the flight

MISSION SPECIFICATION: Pay load: bombs, carried externally and 907kg of ammunition and 4535 kg bombs Crew: one pilot Cruise speed: Mach 2 at sea level Strafe : 5 min Take off and landing: ground of less than x at sea level and a x day Power plants: two turbo fan engines Certification base : military

Phase 1 : engine start and warm up

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Begin weight is wto . end weight is w1 the fuel fraction for this phase is by above definition given by w1/wTO From the suggested fuel fraction table for military fighters W1/wTO = 0.99

Phase 2: TAXIBegin weight is w1. End weight is w2. The fuel fraction for this phase is w2/w1 .From the suggested fuel fraction for military fighters W2/w1 = 0.99

Phase 3: Take offBegin weight is w2. End weight is w3. The fuel fraction for this phase is w2/w1 .From the suggested fuel fraction for military fighters W3/w2 = 0.99

Phase 4: climbBegin weight is w3. End weight is w4. The fuel fraction for this phase is w2/w1 .From the suggested fuel fraction for military fighters ECR = [1/CJ]CR[L/D]cr ln[w4/w3] E=(S/C)/(R/C)= 17000/25.42 =668.7 668.7 =3600/0.8(10)ln(W3/W4) W4/w3 = 0.985

Phase 5: cruiseBegin weight is w4. End weight is w5. The ratio w5/w4 can be estimated from breguet’s range formula which can be written as followsFor jet airplanes RCR = [V/CJ]CR[L/D]cr ln[w4/w5] 600*103 = [(2*340.47*3600)/0.6]*7ln(W4/W5) W5/W4 = 0.979

Phase6: loiterBegin weight is w5. End weight is w6. The fuel fraction for this phase is w6/w5

From the suggested fuel fraction for military fighters W6/W5 = 0.967

Phase7: Descent

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Begin weight is W6. End weight is W7. The fuel fraction for this phase is W7/W6

From the suggested fuel fraction for military fighters W7/W6 = 0.99

Phase8: Dash-outBegin weight is W7. End weight is W8. The fuel fraction for this phase is W8/W7

R = [V/CJ][L/D] ln[w7/w8] 200*103 = [(2*340.47*3600)/0.9](4.5)ln(W7/W8) W8/W7 = 0.983

Phase9: Drop BombsBegin weight is W8. End weight is W9. The fuel fraction for this phase is W9/W8

From the suggested fuel fraction for military fighters W9/W8 = 1NOTE: the bomb load is 4535.92 kg. The total fuel fraction upto this point is found as Mff(1-9) = W9/W8*………….*W1/WTO = 0.891 Wf(1-8) = 0.891*22000 =19602 kg 19602-4535.92= 15066.08 kg

Phase10: Strafe Begin weight is W9. End weight is W10. The fuel fraction for this phase is W10/W9. Strafing time is 5 minutes. Assuming that uring strafing phase maximum military thrust is used.

E = [1/CJ][L/D] ln[w9/w10] E =300s, cj=0.9, L/D=4.5 300=3600*4.5/0.9ln(w9/w10)

W10/W9=0.983Weight correction: 15066.08/19602 = 0.769 W10/W9 =(1-(1-0.983)0.769) =0.987

Phase11: Dash-inBegin weight is W10. End weight is W11. The fuel fraction for this phase is W11/W10

R = [V/CJ][L/D] ln[w7/w8] 200*103 = [(2*340.47*3600)/0.9](4.5)ln(W11/W10) W11/W10 =0.929

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Weight correction: 14809.96/15066 = 0.983 W10/W9 =(1-(1-0.929)0.983) =0.93

Phase12: ClimbBegin weight is w11. End weight is w12. The fuel fraction for this phase is w12/w11.From the suggested fuel fraction for military fighters ECR = [1/CJ]CR[L/D]cr ln[w11/w12] E=(S/C)/(R/C)= 17000/25.42 =668.7 668.7 =3600/0.8(10)ln(W11/W12) W12/w11 = 0.98

Phase13: Cruise inBegin weight is w12. End weight is w13. The fuel fraction for this phase is w13/w12.

M=2.2 , Cj=0.6, L/D=7.5 R=6OOkm RCR = [V/CJ]CR[L/D]cr ln[w12/w13] 600*103 = [(2.2*340.47*3600)/0.6]*7ln(W12/W13) W13/W12 = 0.948

Phase14: DescentBegin weight is w13. End weight is w14. The fuel fraction for this phase is w14/w13.From the suggested fuel fraction for military fighters w14/w13 = 0.99

Phase15: Landing, Taxi, Shut downBegin weight is w14. End weight is w15. The fuel fraction for this phase is w15/w14.From the suggested fuel fraction for military fighters w15/w14=0.995Mff = w15/w14 * w14/w15*………………. W1/wTO

= 0.995*0.99*0.948*0.98*0.93*0.983*0.891Mff =0.745WF(used)=(1-Mff)WTO

=(1-0.745)22000 =5610kgWF =WF(used)+WF(reserve)

=5610(1-25)

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=7102.5kgWOE =WE+WTFO+ Wcrew =8000+0.05(7102.5) +90.7 =8441.325kgWTO =WOE+WF+WPL

=8441.325+7102.5+5442WTO =20985.83kgWE(tent) =WTO-WPL-Wcrew-WF-WTFW

=22000-5442-90.7-7102.5-0.05(7102)WE(tent)=9104.175Verification using Roskam GraphWE =9070 kgPercentage error = [(9104.175-9070)/9070]*100% = 0.38% WTO =22000kg WF =7102.5kg WE =9104.175 kg

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AIRFOIL SELECTION

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NACA 65-410

Thickness: 10.0%Camber: 2.2%Trailing edge angle: 9.2o

Lower flatness: 77.6%

Leading edge radius: 1.1%Max CL: 1.015Max CL angle: 11.0Max L/D: 41.272Max L/D angle: 3.5Max L/D CL: 0.798Stall angle: 3.5Zero-lift angle: -3.0

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http://www.worldofkrauss.com/foils/showplot/1655

NACA 65-210

Thickness: 10.0%Camber: 1.1%Trailing edge angle: 9.3o

Lower flatness: 63.2%Leading edge radius: 1.1%Max CL: 0.85Max CL angle: 11.5

Max L/D: 31.146

Max L/D angle: 3.0

Max L/D CL: 0.547

Stall angle: 3.0Zero-lift angle: -1.5

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http://www.worldofkrauss.com/foils/showplot/1660

WING LOADING CALCULATION

52

WING LOADING

CONSTRAINTS:

Through Vstall

Through landing distance

USING Vstall:

= 0.5*1.2256*(68.33)2(1/1.345)

=313.75 kg/m2

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USING LANDING DISTANCE

R = V2/0.2g

= (1.15* 61.11)2/(0.2*9.81)

= 2517.22m hf = R(1-cosθa) θa = 3W , R=2517.22 hf = 3.449m sa = (50- hf)/tanθa

sa = 225.1m sf = Rsinθa

sf = 131.74m

Landing distance = sa+ sf+ sg

Sg = Landing distance – sa- sf

= 450-225.1-131.74 Sg = 93.16m Also, sg = jN[(2/ρ∞)(w/s)(1/cLmax)](1/2)

Where j = 1.14 N= 3 µ= 0.04 (w/s)= 347.52 kg/m2

Therefore, Using Vstall (W/S) = 313.75 kg/m2

Using landing distance (W/S) =347.52 kg/m2

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THRUST TO WEIGHT RATIO

55

THRUST TO WEIGHT RATIO

To determine wing loading three constraints are used. They are,

Take-off distance Rate of climb Maximum velocity

USING TAKE OFFDISTANCE:

Sg = [1.21(W/S)]/(g ρ∞(CLmax)(T/W) = (1.21*313.75*9.81)/(9.81*1.2256*1.345*[t/w]) Sg = 255.1/(T/W) Vstall = 61.11m/s R = [6.96(Vstall)2]/9.81 θob = cos-1(1-(hob/R)) θob = 5.103 sa = Rsinθob

sa = 235.65 sg + sa = Takeoff distance

183.29/(T/W)+235.65=500 T/W = 0.693

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USING RATE OF CLIMB:

(R/C)max =219.72m/s CDO =0.03ρ∞ =1.2256W/S =313.75kg/m2

(L/D)max = 8.26 Z = 2.011 (T/W) =2.68USING Vmax:W4/WTO = W4/W3*W3/W2*W2/W1*W1/WTO

=0.985*0.99*0.99*0.99 =0.956 W4 =21026.83kg Wmc/W4 =0.5(1+[W5/W4]) =(1+0.979)/2 =0.9895 Wmc =0.9895*21026.83 =20805.6kg Wmc/S =20805.6/70.11 =296.75

AT Cruise alt 17000m ρ = 0.1402kg/m3

T/Wmc=0.5 ρ∞ V∞2(CDO/[W/S])+(2K[W/S])/( ρ∞V∞

2) T/Wmc=2.09

57

ENGINE SELECTION

58

ENGINE SELECTION

From the critical performance parameter estimation, we have thrust to weight ratio, T/W =0.693Where , T = thrust required (TR) W = Take off gross weight (WTO) TR = 0.693*(22000*9.81) TR =149.56kN (Twin engine)It is found that , for our conceptual design, thrust required is above 149.56kN. so it isrequired to select a engine which has a thrust ranging 148 kN-150kN. Name of the engine = Pratt & Whitney PW 1215G No/: of engines = 2 Thrust available = 67-76 kN (per engine)

General characteristics

Type: Turbofan Diameter: 1,422–2,057 millimetres (56.0–81.0 in) Bypass ratio: 9:1

Components

Compressor: Axial flow,1-stage geared fan, 2-3 stage LP, 8 stage HP Combustors: Annular combustion chamber Turbine: Axial, 2-stage HP, 3-stage LP

Performance

Maximum thrust: 14,000–23,000 lbf (62–100 kN)

59

PERFORMANCE CURVES

60

0 100 200 300 400 500 600 7000

0.020.040.060.080.1

0.120.140.16

V vs cl

Velocity in m/s

0 100 200 300 400 500 600 7000.0285

0.029

0.0295

0.03

0.0305

0.031

0.0315

0.032

0.0325

V vs cd

Velocity in m/s

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CL

CD

0 100 200 300 400 500 600 7000

0.51

1.52

2.53

3.54

4.5

V vs l/d

Velocity in m/s

0 100 200 300 400 500 600 7000

100000

200000

300000

400000

500000

600000

V vs tr

Velocity in m/s

62

L/D

TR

HODOGRPH

63

THREE VIEW DIAGRAM

64

3 VIEW DIAGRAM

65

CONCLUSION

66

Design is a very fine nature of creating, here we designed a Multi Role Fighter with retrieved data. Design of anything needs experience and presence of mind , we learnt a lot about design characteristics, governing equations, science of aircraft .

67

REFERENCE:

BIBILIOGRAPHY:

1. Introduction to Flight – John .D.Anderson Jr. – Tata Mc Graw Hill 2010

2. Fundamentals of Aerodynamics - John.D.Anderson Jr – fifth edition - Tata Mc Graw Hill 2010

3. Aircraft Design Projects for engineering students - Lloyd R. Jenkinson - James F.

Marchman - third edition - Butterworth-Heinemann

WEBSITES:

1. www.naca/aerofoil.gov

2. www.worldaircraftdierctory.com

3. www.lockheedmartin.com

4. www.northropgrumman.com

5. www.sukhoi.org/eng

6. www.migavia.ru/eng

7. www.worldofkrauss.com

8. And other websites related to design of aircrafts.

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adp 1 : multi-role combat aircraft

Documents

leading edge

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developing

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